Method for Manufacturing Nanostructured Powder by Wire Explosion in Liquid and Device for Manufacturing the Same

ABSTRACT

The present invention relates to a method for manufacturing the nanostructured powder by a wire explosion in liquid and a device for manufacturing the same. To be more specific, the object of the invention is to provide a method for manufacturing the nanostructured powder by a wire explosion in liquid and a device for manufacturing the same, in which, a metal wire ( 18 ) is vaporized in liquid ( 14 ) by generating an electrical explosion using the same principle al in gas, with the characteristic of pulsed power, even though the liquid ( 14 ) with a low conductivity is used, and the nanostructured powder of a metal wire ( 18 ) is produced in the space made by the volume expansion of vaporized vapour, all of which was performed with an understanding that electrical explosion is not so different in principle weather in gas or in liquid. By achieving this object, the present invention can provide an advantage of natural disperse of the nanostructured powder into a liquid, hence either the agglomeration between powder particles or the surface oxidation of the nanostructured powder is not generated, as the powder is not in contact with oxygen in liquid. Moreover, the classification according to size becomes possible with the reduction of the number of processes, hence providing an advantage of an effective application of the nanostructured powder an the economic ripple effect thereto.

TECHNICAL FIELD

The present invention relates to a method for manufacturing nanostructured powder by a wire explosion in liquid and a device for manufacturing the same, and more particularly, to a method for manufacturing nanostructured powder by a wire explosion in liquid and a device for manufacturing the same, which can prevent the problems caused when manufacturing nanostructured powder by a wire explosion in gas in the related art, such as a phenomenon of agglomeration among nanostructured powder particles, a phenomenon of oxidation on the surface of nanostructured powder, etc., and also enable the classification of nanostructured powder by size due to its excellent dispersibility, and as a result, enabling an effective application of nanostructured powder and its great economic ripple effect.

BACKGROUND ART

In recent years, the technological development of nanostructured powder as a new material has been recognized as being very important as it can be applied to base technology of new fields, including the nano-devices.

A nanostructured powder material can display an unique electromagnetic, mechanical and catalytic property which cannot be obtained through existing materials due to their minute material structure (100 nm or less) and the increased surface thereupon, and therefore there is no doubt that there will be a new demand over the whole industry as the post-generation functional material for super-high strength part, magnetic part, thermocouple, sensor, filter, catalyst, etc.

According to the advancement of the high-tech industry, parts and systems move toward higher performance and miniaturization, and the structural particle with the phenomenological length of micron or sub-micron is currently used for determining physical/chemical/biological properties.

Accordingly, the significance of nano technology that it is a technology to overcome the limits of the existing technologies in terms of higher performance and miniaturization of parts and systems, while it is recognized as the model for the future technology as well as an essential element for the development of high-tech products as a new performance may be revealed with the reduction of the phenomenological length.

At the present, various methods for manufacturing nanostructured powder from certain materials are known to us; however, among them is a widely known technology for manufacturing nanostructured metal powder by a wire explosion using pulsed power and is still actively studied today.

The method for manufacturing nanostructured powder using pulsed power has much significance in the aspect of industrial application, while also having much economic advantage, compared to other methods for manufacturing nanostructured powder.

The conventional method for manufacturing nanostructured metal powder by wire explosion using pulsed power is described as in the following:

A wire explosion in gas is used in the conventional method for manufacturing nanostructured metal powder, and it is conducted by including the steps of providing a predetermined chamber filled with air or inert gas, feeding a metal wire into the chamber, electrically exploding and vaporizing the metal wire inside the chamber using pulsed power, and collecting the nanostructured metal powder produced that is cooled and condensed by inert gas using an air filter.

However, the conventional method for manufacturing nanostructured powder using wire explosion in gas aforementioned has the following problems:

First of all, it has a disadvantage that most of nanostructured metal powder is exposed to the air and hence easily oxidized, and has a difficulty in its handling as the risk of dust explosion is inherent during the process.

Second, there is an inconvenience of periodical cleaning of the deposited powder due to frequent dielectric breakdown caused by the powder deposited in the chamber during the process of manufacturing nanostructured powder, and accordingly, there is a disadvantage of exceptionally low productivity and workability.

Third, the nanostructured powder collected in air tends to agglomerate in its characteristic, and as a result, there is a difficulty in classification according to the size.

Fourth, there is an aspect of being inefficient and uneconomical in the process, since an essential process of dispersing nanostructured powder into a dispersing agent is further required in order to use the agglomerated powder.

The present invention has been studied and developed in consideration of the above issues, and considering that electrical explosion is not so different in principle between the one in gas and in liquid, the object of the invention is to provide a method for manufacturing nanostructured powder by a wire explosion in liquid, as well as a device for manufacturing the same, in which as a feature of pulsed power a metal wire is vaporized in liquid by generating an electrical explosion using the same principle as in gas despite the low conductivity of the liquid and nanostructured powder of a metal wire is produced in the space made through the volume expansion of vaporized vapour.

The nanostructured powder, produced by such a method of the present invention, can provide an advantage that it is naturally dispersed into liquid so that the agglomeration between powder particles does not occur at all, and also the surface oxidation of powder is not generated as it is not contacted with oxygen in liquid.

DISCLOSURE

In order to accomplish the aforementioned object, a method for manufacturing nanostructured powder by wire explosion in liquid, comprising: the first process of electrically exploding a metal wire using pulsed power in the chamber filled with a liquid (dispersing solvent); the second process of producing nanostructured powder by vaporizing the metal wire in liquid; and the third process of concentrating or collecting the produced nanostructured powder.

As an appropriate embodiment, the aforementioned first process is characterized with a progress including a step to provide a chamber filled with a liquid; a step to continuously feed a metal wire into the liquid from an upper side of the chamber; and a step to flow in 0.1-100 kJ pulsed power into the metal wire in liquid to generate an electrical explosion.

As another preferred embodiment, the aforementioned second process is characterized by including a step to vaporize the metal wire in liquid due to an electrical explosion; and a step to produce nanostructured powder of the metal wire in the space made by the volume expansion of vaporized steam.

As still yet another preferred embodiment, the aforementioned third process is characterized by including a step to discharge the liquid dispersed (suspended) with nanostructured powder from the chamber; a step to uniformly inject the discharged liquid into a collecting filter with a spray; and a step to pick up nanostructured powder filtered by the collecting filter.

Or, the aforementioned third process is characterized by including a step to discharge the liquid dispersed (suspended) with nanostructured powder from the chamber; and a step to evaporate the discharged liquid by an evaporation classification method to collect or to condense the nanostructured powder for pickup.

At this time, the main characteristic lies in that the liquid (dispersing solvent) was any one selected from oil, distilled water, insulating oil, solvent, acetone, ethanol, or gasoline.

In particular, one of the main characteristics is the fact that a number of collecting filters with different sizes of mesh (hole diameter) are vertically arranged to collect nanostructured powder in classification according to size.

Also, another characteristic is the fact that when nanostructured powder filtered by the collecting filter is picked up, it is picked up in a state where the nanostructured powder is covered with the liquid (dispersing solvent).

Furthermore, another characteristic lies in a step of reflowing the liquid passing through the collecting filter into the chamber is further progressed by a liquid circulating motor.

In order to accomplish the above-mentioned object, a device is provided for manufacturing nanostructured powder by a wire explosion in liquid, comprising a chamber having a structure divided into an upper space and a lower space by an insulator; a liquid (dispersing solvent) filled in the lower space; a wire feeding device provided in the upper space; a wire explosion device provided in the lower space; a nanostructured powder collecting device arranged for connection with a bottom corner location of the lower space; and a recirculation device for recirculating the liquid from the nanostructured powder collecting device to the lower space.

As an appropriate embodiment, the aforementioned insulator of the chamber is characterized in that a hollow wire guide for feeding the wire is mounted in the insulator of the chamber, while a grounding electrode is further mounted in the lower space filled with the liquid.

As another preferred embodiment, the aforementioned wire feeding device is characterized with an inclusion of a wire feeding device includes a wire roll wound with a metal wire, a pair of feeding rollers for feeding the wire being unfolded from the wire roll into the lower space through a wire guide, and an electric motor connected with the wire roll and the rotational axis of a pair of the feeding rollers.

As still yet another preferred embodiment, the aforementioned wire explosion device is characterized with an inclusion of a high voltage electrode mounted on a bottom surface of the lower space in the chamber, a trigger switch connected with the high voltage electrode, a capacitor connected with the switch, a charging device for charging the capacitor with high voltage, a controller for sensing the rotation angle of the feeding motor to generate a trigger signal in the switch.

Furthermore, the aforementioned nanostructured powder collecting device is characterized with an inclusion of a cistern tank having a predetermined volume, a valve imbedded pipe connected for communicating the lower space of the chamber with an upper space of the cistern tank, a spray mounted integrally at the end of the pipe to be arranged in an upper end space of the cistern tank, and a number of collecting filters vertically mounted at equal intervals under the spray in the interior space of the cistern tank.

At this time, the number of the collecting filters aforementioned is characterized with an arrangement of the one having a large mesh size (hole diameter) located at higher level, while the one having a small mesh size is located at lower level.

Furthermore, the aforementioned recirculation device is characterized with an inclusion of a circulation pipe linked for a connection between a lower end of the cistern tank and an upper end of the lower space in the chamber, an on-off valve mounted on the circulation pipe, and a liquid circulating pump.

A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings hereinafter.

As illustrated herein, the attached FIG. 1 is a configuration view illustrating a device for manufacturing nanostructured powder by a wire explosion in liquid according to the present invention, while FIG. 2 is a flow chart illustrating a method for manufacturing nanostructured powder by a wire explosion in liquid according to the present invention.

As described above, the main object of the present invention is to provide an advantage of naturally dispersing the nanostructured powder of a metal wire into liquid and hence not resulting in the phenomenon of agglomeration between powder particles or in the generation of surface oxidation of powder as the powder is not in contact with oxygen in liquid, by applying pulsed power to a metal wire to generate an electrical wire explosion in liquid.

The method for manufacturing nanostructured powder, as well as a detailed explanation for each element of a device for manufacturing nanostructured powder according to the present invention, will be described in detail.

As the site where an electrical explosion takes place in a device for manufacturing nanostructured powder according to the present invention, a chamber (10) with a pre-determined volume is provided, and the interior of this chamber (10) is divided into an upper space (12) and a lower space (14) by a plate-shaped insulator (16).

The lower space (14) is filled with a liquid (dispersing solvent), and any one selected from oil, distilled water, insulating oil, solvent, acetone, ethanol, or gasoline can be used as this liquid.

The upper space (12) is provided with a wire feeding device, and the wire feeding device includes a wire roll (20) stored with a winding of a metal wire (18), and a pair of feeding rollers (22) for feeding downward the metal wire (18) unfolded from the wire roll (20).

Furthermore, an electric motor (not shown) is connected with the wire roll (20) and the rotational axis of a pair of the feeding rollers (22).

On the other hand, as the path for providing the metal wire (18) that is fed downward by a pair of the feeding rollers (22) to the lower space (14), a hollow wire guide (24) is mounted on the insulator (16) of the chamber (10) to vertically pass through.

Furthermore, a grounding electrode (26) is attached to the lower space (14) while being immersed in liquid, and this will act as a grounding means for electrical explosion, which will be described later.

Here, a wire explosion device is installed at the bottom side of the lower space (14).

As a configuration of the wire explosion device, a high voltage electrode (28) is mounted at the bottom of the lower space (14) in the chamber (10), and a spark gap switch (30) connected with the aforementioned high voltage electrode (28) is arranged at the outside of the lower space (14).

Furthermore, a capacitor (32) charged with high voltage is connected to the switch (30), and a charging device (34) for charging high voltage is connected to this capacitor (32).

In particular, a controller (36) is connected to the aforementioned switch (30), and this controller (36) senses either the rotation angle of an electric motor (not shown) that provides a rotational driving force to a pair of feeding rollers (22) or the reduction of resistance generated through contacting a wire with the electrode, thereby taking control of generating a trigger signal to the switch (30).

Here, the process of producing nanostructured powder of a metal wire (18) in the lower space (14) of the aforementioned chamber (10) by the aforementioned wire feeding device and the wire explosion device may be described as in the following:

As a wire roll (20) of the aforementioned wire feeding device rotates in one direction, this unfolded metal wire (18) is fed to the lower space (14) of the chamber (10) by a pair of feeding rollers (22).

In other words, a metal wire (18) that is fed downward by a pair of feeding rollers (22) is continuously provided to the high voltage electrode (28) of the lower space (14) through the wire guide (24).

Subsequently, when the controller (36) transmits a trigger signal to the switch (30) as it senses the rotation angle of an electric motor (not shown) for rotating a pair of the feeding rollers (22) or the reduction of resistance that is generated by contacting a wire with the electrode, the pulsed power provided from the capacitor (32) flows to the metal wire through the high voltage electrode (28) with a switch on, thereby generating an electrical wire explosion.

At this time, a wire explosion is generated with 0.1-100 kJ pulsed power flows into the metal wire in liquid.

The metal wire (18) is vaporized in liquid with such electrical explosion, and nanostructured powder of the metal wire (18) is produced in the space made by the volume expansion of vaporized vapour.

Here, a device for collecting nanostructured powder produced as described above and the process thereto may be described as in the following:

As a configuration of the aforementioned nanostructured powder collecting device, a cistern tank (40) with a predetermined volume is provided, and an upper side of the interior space in the aforementioned cistern tank (40) is linked by a connection with a corner location of the lower space (14) in the chamber (10) through a valve imbedded pipe (42).

Furthermore, a spray (44) having a shape that widens downward is adhered to the end of the aforementioned pipe (42) inside the aforementioned cistern tank (40), and a number of collecting filters (46) are vertically adhered at equal intervals in the interior space of the cistern tank (40) under the spray.

At this time, among a number of the aforementioned collecting filters (46), the filter with a large mesh size (hole diameter) is mounted at higher level, while the filter with a small mesh size is mounted at lower level, thereby allowing nanostructured powder to be selectively collected by sizes.

Here, a state in which nanostructured powder is collected by a nanostructured powder collecting device as configured in the above may be described as in the following:

As described above, the liquid dispersed (suspended) with nanostructured powder of a metal wire (18) in liquid is discharged from the aforementioned chamber (10) by an electrical explosion, and the discharged liquid is provided to the spray (44) through the aforementioned valve imbedded pipe (42) and is uniformly injected into the aforementioned collecting filters (46) through this spray (44).

Accordingly, the nanostructured powder with the largest size is filtered in the uppermost collecting filter (46), while the nanostructured powder with the smallest size is filtered in the lower-most collecting filter (46), thereby allowing nanostructured powder to be collected while being classified according to size.

At this time, while the nanostructured powder filtered by the collecting filter (46) is being picked up, it is more appropriate to collect the nanostructured powder in a state of being covered (immersed) with the liquid (dispersing solvent), in order to prevent an oxidation of the nanostructured powder through contact with air.

On the other hand, the device for manufacturing nanostructured powder in the present invention further includes a recirculation device that recirculates the discharged liquid to the lower space (14) of the chamber (10).

The aforementioned recirculation device includes a circulation pipe (48) that connects the lower end of the cistern tank (40) with the lower space (14) of the chamber (10), an on-off valve (50) mounted on the circulation pipe (48), and a liquid circulating pump (52).

Accordingly, the liquid in a state where the nanostructured powder is filtered by passing through the collecting filters (46) is pumped by the aforementioned circulating pump (52) and reflowed into the lower space (14) of the chamber (10).

As described above, by inducing an electrical explosion through applying pulsed power to the metal wire in liquid, the nanostructured powder of the metal wire is produced and dispersed, thereby preventing agglomeration among nanostructured powder particles. In particular, contact with air is blocked off since nanostructured powder is produced in liquid, thereby effectively preventing the oxidation. Furthermore, the nanostructured powder in liquid may be selectively collected by size, thereby allowing its classification according to size.

DESCRIPTION OF DRAWINGS

The above and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompany drawings, which include:

FIG. 1 is a configuration view illustrating a device for manufacturing the nanostructured powder by a wire explosion in liquid according to the present invention;

FIG. 2 is a flow chart illustrating a method for manufacturing the nanostructured powder by a wire explosion in liquid according to the present invention;

FIG. 3 is a photograph taken at high speed, illustrating a state in which the nanostructured silver powder is manufactured by a wire explosion in liquid according to the present invention;

FIG. 4 is a view illustrating a voltage and current waveform of a wire explosion in liquid;

FIG. 5 is a microphotograph illustrating the nanostructured silver powder that is manufactured according to the method for manufacturing the nanostructured powder by a wire explosion in liquid according to the present invention;

FIG. 6 is an analytical graph by an X-ray diffraction method for confirming that the nanostructured powder of the invention is pure nanostructured silver powder;

FIG. 7 is a photograph illustrating the experimental results of sedimentation for the nanostructured silver powder manufactured in liquid according to the present invention, and the nanostructured silver powder manufactured in gas in the related art;

FIG. 8 is a SEM photograph illustrating the nanostructured copper powder in the embodiment 5, manufactured in liquid according to the present invention; and

FIG. 9 is a graph by an XRD analytic result illustrating the nanostructured copper powder in the embodiment 5, manufactured in liquid according to the present invention.

BEST MODE

Reference will now be made in detail to the preferred embodiment of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below so as to explain the present invention by referring to the figures.

EMBODIMENTS 1-4

As an embodiment of a method for manufacturing the nanostructured powder according to the present invention, a predetermined chamber was filled with liquid (distilled water), into which a silver (Ag) wire was provided and the pulsed power was flowed into at 1, 2, 3 and 4 kJ, respectively, to generate an electrical explosion, and due to this electrical explosion, the nanostructured powder of the metal wire was produced in a dispersed state in liquid.

More specifically, as seen in the high-speed photograph of FIG. 3, as an electrical explosion was generated by flowing pulsed power at 1, 2, 3 and 4 kJ, respectively, where a silver wire of 0.3 mm in diameter and 25 mm in length was immersed in distilled water, a metallic vapour plasma was generated in the space produced in liquid by an impulse wave, and simultaneously, the metal (silver) vapour was condensated to produce the nanostructured powder, ultimately producing the nanostructured silver powder dispersed in liquid.

Subsequently, the nanostructured aluminum powder in liquid was selectively collected according to sizes using a number of collecting filters.

EMBODIMENTS 5

As an embodiment of a method for manufacturing the nanostructured powder according to the present invention, a predetermined chamber was filled with liquid (acetone), and then a copper wire of 0.3 mm in diameter and 40 mm in length was discharged 200 times in acetone solvent to produce the nanostructured powder, and the nanostructured powder was collected using a rotary evaporator for observation.

COMPARATIVE EXAMPLE 1

According to the conventional method for manufacturing the nanostructured powder, an electrical explosion was generated by flowing pulsed power at 2 kJ into a silver wire in the chamber (in gas), and due to this electrical explosion, the nanostructured powder of the aluminum metal wire was cooled/condensated and produced in gas.

COMPARATIVE EXAMPLE 2

According to the conventional method for the manufacturing nanostructured powder, an electrical explosion was generated by flowing pulsed power at 2 kJ into a silver wire in the chamber (in gas), and due to this electrical explosion, the nanostructured powder of the copper metal wire was cooled/condensated and produced in gas.

EXPERIMENTAL EXAMPLE 1 Experiment of Voltage and Current Waveform

As illustrated herein, FIG. 4 displays a voltage and current waveform of a wire explosion in liquid.

A current curve properly represents a feature shown by an electrical explosion. In other words, it shows the loss of conductivity due to vaporization and the abrupt current reduction thereto.

Furthermore, it properly represents a process of resolving the abrupt current reduction then converting to a damped vibration mode, with the resumption of conducting a current by the plasma, generated at the moment of an explosion. Moreover, a voltage curve represents a feature of decreasing at the beginning of discharge then slightly increasing at the moment when the wire explodes.

As illustrated herein, FIG. 5 is a SEM (Scanning Electron Microscope) photograph showing the nanostructured silver powder manufactured by a wire explosion in liquid. It can be seen that the nanostructured powder is composed of spherical nanoparticles of about 100 nm, and it was confirmed that the manufactured nanostructured powder was pure nanostructured silver powder through an analysis by an X-ray diffraction method as in FIG. 6. Here, an XRD analysis is an analysis method for irradiating the crystalline structure of a material to find out the type of material, and the position and the size of peaks as illustrated in FIG. 6 is compared with an already known database in order to assume what material it is. The graph in FIG. 6 has the peaks of silver material as a whole.

In this manner, according to the embodiments 1-4 of the present invention, the nanostructured silver powder was produced and dispersed in liquid by an electrical explosion, and it could be confirmed that uniformly spherical nanoparticles of about 100 nm could be obtained, in comparison to the nanostructured powder produced in gas, according to the comparative example.

EXPERIMENTAL EXAMPLE 2

According to the embodiments 1-4 of the present invention, an experiment on the sedimentation state was conducted for the nanostructured silver powder manufactured in liquid and the nanostructured silver powder manufactured in gas according to the comparative example, and the results are as illustrated herein in photographs of FIG. 7.

The Nanostructured silver powder contained in the two bottles on the left side in photographs (a) and (b) of FIG. 7 is the nanostructured powder manufactured in gas, and the change of color to transparent by sedimentation could be observed after 4 days, and the nanoparticles cohered with each other.

On the other hand, the nanostructured silver powder manufactured in liquid according to the present invention (contained in a bottle on the most right side in photographs (a) and (b) of FIG. 7 as illustrated herein) was uniformly dispersed and not precipitated in liquid even after 4 days, neither did the powder particles cohere with each other.

As described above, in order to manufacture the nanostructured powder with good quality, a method for manufacturing nanostructured powder in liquid according to the present invention is much more excellent, economical, and effective than the conventional method for manufacturing nanostructured powder in gas.

EXPERIMENTAL EXAMPLE 3

The copper powder manufactured according to the embodiment 5 was collected and a photograph was taken by an electron microscope, as seen in the SEM photograph illustrated in FIG. 8. It was confirmed that the specific surface area measured by BET was 40.84 m²/g, and the average granularity when converted into diameter was 17 nm.

Furthermore, the copper powder manufactured according to the embodiment 5 was analyzed by an XRD method, and the result showed that each peak represents the peaks of copper metal as a whole, and also that this copper powder was pure non-oxidized nanostructured metal powder, as seen under the graph of FIG. 9.

INDUSTRIAL APPLICABILITY

As described above, a method of manufacturing the nanostructured powder by a wire explosion in liquid and a device for manufacturing the same has the following advantages.

1) It has an advantage that the nanostructured powder of a metal wire is produced and dispersed in liquid by feeding the metal wire in liquid in the chamber while flowing a pulsed power to generate an electrical explosion, thereby completely preventing a agglomeration of the nanostructured powder, and remarkably reducing the oxidation in nanostructured powder, by blocking off the contact with air by the liquid.

2) By excluding a process of eliminating oxygen on the surface of the nanostructured powder and a process required for dispersing agglomerated powder in a dispersing agent in the related art, cost reduction and more efficient process for manufacturing nanostructured powder can be achieved.

3) According to the present invention, the nanostructured powder is produced in a dispersed (suspended) state, which prevents the deposit in the chamber, as well as the dielectric breakdown due to deposited powder, thereby improving the productivity of manufacturing nanostructured powder.

4) According to the present invention, the nanostructured powder is dispersed but not agglomerated in liquid, and hence enabling its classification through selective collection by size, thereby enhancing the added value.

Although a few exemplary embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art, that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents. 

1. A method for manufacturing nanostructured powder by a wire explosion in liquid, comprising: exploding a metal wire electrically using pulsed power in the chamber filled with a liquid (dispersing solvent) selected from the group consisting of oil, distilled water, insulating oil, solvent, acetone, ethanol and gasoline; vaporizing the metal wire in liquid; and concentrating or collecting the produced nanostructured powder.
 2. The method for manufacturing nanostructured powder by a wire explosion in liquid according to claim 1, wherein the first process is progressed by including a step of providing the chamber filled with a liquid; a step of continuously feeding a metal wire into the liquid from an upper side of the chamber; and a step of flowing 0.1-100 kJ pulsed power into the metal wire in the liquid to generate an electrical explosion.
 3. The method for manufacturing nanostructured powder by a wire explosion in liquid according to claim 1, wherein the second process includes a step of vaporizing the metal wire in liquid due to an electrical explosion; and a step of producing nanostructured powder of the metal wire in the space made by the volume expansion of vaporized vapour.
 4. The method for manufacturing nanostructured powder by a wire explosion in liquid according to claim 1, wherein the third process includes a step of discharging the liquid dispersed (suspended) with nanostructured powder from the chamber; a step of uniformly injecting the discharged liquid into a collecting filter using a spray; and a step of picking up nanostructured powder filtered by the collecting filter.
 5. The method for manufacturing nanostructured powder by a wire explosion in liquid according to claim 1, wherein the third process includes a step of discharging the liquid dispersed (suspended) with nanostructured powder from the chamber; and a step of evaporating the discharged liquid by an evaporation classification method to retrieve or concentrate nanostructured powder for pickup.
 6. (canceled)
 7. The method for manufacturing nanostructured powder by a wire explosion in liquid according to claim 4, wherein a plurality of collecting filters having different sizes of mesh (hole diameter) are vertically arranged to collect nano-structured powder through classification according to size.
 8. The method for manufacturing nanostructured powder by a wire explosion in liquid according to claim 4, wherein when nanostructured powder filtered by the collecting filter is picked up, it is picked up in a state that the nanostructured powder is covered with the liquid (dispersing solvent) to prevent an oxidation.
 9. The method for manufacturing nanostructured powder by a wire explosion in liquid according to claim 4, wherein a step of reflowing the liquid passing through the collecting filter into the chamber is further progressed by a liquid circulating motor.
 10. A device for manufacturing nanostructured powder by a wire explosion in liquid, comprising: a chamber having a structure divided into an upper space and a lower space by an insulator; a liquid (dispersing solvent) selected from the group consisting of oil, distilled water, insulating oil, solvent, acetone ethanol and gasoline filled in the lower space; a wire feeding device as a configuration provided in the upper space, including a wire roll wound with a metal wire, a pair of feeding rollers for feeding the wire being unfolded from the wire roll into the lower space through a wire guide, and an electric motor connected with the wire roll and the rotational axis of a pair of the feeding rollers; a wire explosion device as a configuration provided in the lower space, including a high voltage electrode mounted on a bottom surface of the lower space in the chamber, a trigger switch connected with the high voltage electrode, a capacitor connected with the switch, a charging device for charging the capacitor with high voltage, a controller for sensing the rotation angle of the feeding motor to generate a trigger signal in the switch; a nanostructured powder collecting device as a configuration arranged for communicating with a bottom corner location of the lower space, including a cistern tank having a predetermined volume, a valve imbedded pipe connected for communicating the lower space of the chamber with an upper space of the cistern tank, a spray mounted integrally at the end of the pipe for being arranged in an upper end space of the cistern tank, and a number of collecting filters vertically mounted at equal intervals under the spray in the interior space of the cistern tank; and a recirculation device as a configuration for recirculating the liquid from the nanostructured powder collecting device to the lower space, including a circulation pipe connected for communicating between a lower end of the cistern tank and an upper end of the lower space in the chamber, an on-off valve mounted on the circulation pipe, and a liquid circulating pump.
 11. The device for manufacturing nanostructured powder by a wire explosion in liquid according to claim 10, wherein a hollow wire guide for feeding the wire is mounted in the insulator of the chamber, and a grounding electrode is further mounted in the lower space filled with the liquid.
 12. The device for manufacturing nanostructured powder by a wire explosion in liquid according to claim 10, wherein among a number of the collecting filters, the filter with a large mesh size (hole diameter) is located at upper level, while the filter with a small mesh size is located at the lower level. 